Article Text
Abstract
Introduction Non-alcoholic fatty liver disease (NAFLD) is the commonest cause of referral to liver clinics, and accounts for around 11% of new patients. Despite this little is known of the typical pattern of liver biochemical abnormalities in this group. Many algorithms primarily use transaminases as their primary biochemical analyte. The aim of this project was to clarify common patterns and to determine their clinical significance.
Method This was a single-centre, retrospective database study of all patients referred to a specialist NAFLD clinic between May 2006 and May 2009. Patients with any co-existing cause of liver disease, a history of excess alcohol or HOMA less than three were excluded from subsequent data analysis. For the 143 patients who remained a database search for contemporaneous blood results and clinical history was performed.
Results Mean age at the time of referral was 55.8 years (SD 15.9). M/F=1:1.04. 54% were diabetic; 62% had hyperlipidaemia and 58% had a history of hypertension. 23 (16%) were deemed to be cirrhotic in the initial series of investigations. In this cohort elevated GGT was the commonest biochemical abnormality, present in 76.2% of referrals. GGT was elevated above 100 U/L in 38.5% of patients. In contrast, elevated ALT (>50U/L) was present in 58.0% of referrals; and was above 100U/L in 10.5%. Mixed ALT and GGT abnormalities were the commonest pattern of LFT abnormalities, present in 46.9%. A cholestatic pattern (here defined as an abnormal GGT but normal ALT) was present in 30.1% of referrals; elevated transaminases as an isolated abnormality were present in only 11.9% of referrals. On univariate analysis the only factors associated with elevated GGT was female gender (p=0.009) and the presence of cirrhosis (p=0.003). GGT >100 was associated with cirrhosis and increasing age on univariate analysis, however on multivariate analysis only the presence of cirrhosis remained statistically significant (p=0.005). Elevated ALT had no such association with cirrhosis and was negatively associated with the presence of diabetes and increasing age.
Conclusion To date emphasis has been placed on serum transaminases in screening for NAFLD. However, in our cohort an elevated GGT was the commonest biochemical abnormality and, unlike transaminases, this was associated with the presence of cirrhosis. Biochemical profiles that omit GGT will be inadequate in screening for NAFLD.